Inflatable structures may be used as human habitats, storage facilities, laboratories, or for other sheltering applications. When such a structure is used in a remote or environmentally adverse region, such as sub-zero regions, emergency shelters after harsh weather storms, or outer space environments, its deployment can be accomplished efficiently and quickly, minimizing exposure of workers to the extremes of weather or other environmental hazards. Additionally, such structures can be transported to a desired site while in a compact, deflated mode and later deployed by inflation at the site to form larger, self-supporting structure, thereby reducing the amount of space required during transport. Their use also enables the construction of self-supporting structures of greater size and interior volume but of lighter weight than structures made of conventional, rigid materials, thereby reducing weight during transport.
The basic construction of an inflatable, cylindrical structure or module and its deployment in exoatmospheric space is disclosed in detail in U.S. Pat. No. 6,231,010 (the '010 patent) and U.S. Pat. No. 6,547,189 (the '189 patent), both of which are hereby incorporated by reference. As disclosed in these two patents, the flexible outer walls of such inflatable space modules are complex structures incorporating multiple layers of flexible materials selected to perform their respective functions. The wall structure of such a module, when the module is in its non-deployed mode, is folded upon itself to form a compact unit. As the module is inflated, gas under pressure introduced into the interior of the module increases the internal pressure causing the wall structure to expand outwardly. In the process, the inflation and outward expansion of the module exerts stresses upon the outer wall structure of the inflatable module. The loads resulting from inflation of the module are largely born by a restraint layer, which is designed to sustain the resultant loads. The restraint layer typically comprises a webbing formed of multiple, orthogonal straps of high tensile strength material such as Kevlar® or Vectran®.
Inflatable space modules have generally included a sidewall portion that, in the deployed mode, is a substantially cylindrical configuration. For example, the inflatable cylindrical structure illustrated and described in the '010 and '189 patents comprise longitudinally extending modules having substantially cylindrical wall portions that are closed at opposite ends. In some embodiments, the design for such modules has included a rigid, longitudinally extending central core structure. The webbing of load-bearing straps extend generally longitudinally about the module or circumferentially around the cylindrical wall portion to sustain the loads that result as the module is inflated, with the flexible wall structure being expanded to form a semi-rigid, self-supporting structure. When inflated and deployed, the structure expands into a longitudinally extending, generally cylindrical module, the volume of which may be sufficiently large to permit use of the module as an orbiting human habitat.